盐岩在库车拗陷中的作用

FUNCTION OF SALT ROCK IN KUQA SAG

库车拗陷的勘探实践表明,盐层与油气密切相关。通过对2条地震测线的分析发现,盐层、盐上地层、盐下地层变形看似孤立,实际相互影响。盐层构造变形一般发育在古隆起上部,盐上构造变形主要发生在盐枕构造的翼部,无盐地区主要发育基底卷入式构造。膏盐层可以延缓盐下地层烃源岩的热演化程度,可以改善盐下储层的储集性能;膏盐层本身也有可能成为油气储集层;膏盐层具有形成超压封闭和物性封闭的双重封闭机制,对盐下油气藏的保存极为有利;膏盐层的塑性流动特性,使得盐下构造圈闭在强烈的构造挤压中得以保存。

The exploration of Kuqa sag shows that the salt layers are closely related to hydrocarbon.Two seismic profiles are analyzed to find out that salt layers,the strata above and below salt seem isolated,but are interactive actually.The salt layers deform on palaeohigh,the strata above salt deform on the wings of salt pillow.The distributing range of salt layers controls the deuteric development of structures in this basin,the propagation of structural deformation ceases where salt layers vanish.The deformation in the area where salt layers develop can be divided into three parts,i.e.deformation in salt layers,deformation above salt layers and deformation below salt layers,which are interconnected but different.The area without salt mostly develops structures that involve basement.Salt layers can delay the thermal evolution of source rocks which are below salt layers and improve reservoir rocks.Salt layers can seal oil and gas reservoir with super pressure and physical property,it is in favor of the preservation of oil and gas below salt layers.Owing to the plastic flow of salt layers,the structural traps below salt layers are conserved after intense tectonic compression.